feat(smart-triggers): Add api handler for smart trigger processing at runtime

src/main/java/io/cryostat/agent/remote/SmartTriggersContext.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright The Cryostat Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.cryostat.agent.remote;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import io.cryostat.agent.triggers.TriggerEvaluator;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.sun.net.httpserver.HttpExchange;
+import jakarta.inject.Inject;
+import org.apache.http.HttpStatus;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class SmartTriggersContext implements RemoteContext {
+
+    private Logger log = LoggerFactory.getLogger(getClass());
+    private TriggerEvaluator evaluator;
+    private ObjectMapper mapper;
+
+    @Inject
+    SmartTriggersContext(ObjectMapper mapper, TriggerEvaluator evaluator) {
+        this.evaluator = evaluator;
+        this.mapper = mapper;
+    }
+
+    @Override
+    public void handle(HttpExchange exchange) throws IOException {
+        try {
+            String mtd = exchange.getRequestMethod();
+            switch (mtd) {
+                case "GET":
+                    // Query the currently loaded smart triggers
+                    exchange.sendResponseHeaders(HttpStatus.SC_OK, BODY_LENGTH_UNKNOWN);
+                    try (OutputStream response = exchange.getResponseBody()) {
+                        mapper.writeValue(response, evaluator.getDefinitions());
+                    }
+                    break;
+                case "POST":
+                    try (InputStream body = exchange.getRequestBody()) {
+                        SmartTriggerRequest req = mapper.readValue(body, SmartTriggerRequest.class);
+                        boolean resp = evaluator.append(req.definitions);
+                        if (!resp) {
+                            exchange.sendResponseHeaders(
+                                    HttpStatus.SC_BAD_REQUEST, BODY_LENGTH_NONE);
+                        } else {
+                            exchange.sendResponseHeaders(HttpStatus.SC_ACCEPTED, BODY_LENGTH_NONE);
+                        }
+                    } catch (Exception e) {
+                        log.warn("Smart trigger serialization failure", e);
+                        exchange.sendResponseHeaders(HttpStatus.SC_BAD_GATEWAY, BODY_LENGTH_NONE);
+                    }
+                    break;
+                case "DELETE":
+                    try (InputStream body = exchange.getRequestBody()) {
+                        SmartTriggerRequest req = mapper.readValue(body, SmartTriggerRequest.class);
+                        boolean resp = evaluator.remove(req.definitions);
+                        if (!resp) {
+                            exchange.sendResponseHeaders(
+                                    HttpStatus.SC_BAD_REQUEST, BODY_LENGTH_NONE);
+                        } else {
+                            exchange.sendResponseHeaders(HttpStatus.SC_ACCEPTED, BODY_LENGTH_NONE);
+                        }
+                    } catch (Exception e) {
+                        log.warn("Smart trigger serialization failure", e);
+                        exchange.sendResponseHeaders(HttpStatus.SC_BAD_GATEWAY, BODY_LENGTH_NONE);
+                    }
+                    break;
+                default:
+                    log.warn("Unknown request method {}", mtd);
+                    exchange.sendResponseHeaders(
+                            HttpStatus.SC_METHOD_NOT_ALLOWED, BODY_LENGTH_NONE);
+                    break;
+            }
+        } finally {
+            exchange.close();
+        }
+    }
+
+    @Override
+    public String path() {
+        return "/smart-triggers/";
+    }
+
+    static class SmartTriggerRequest {
+
+        // This is fine as one string, the TriggerParser can handle it
+        // if there are multiple triggers defined.
+        public String definitions;
+    }
+}

src/main/java/io/cryostat/agent/triggers/TriggerEvaluator.java

@@ -30,7 +30,8 @@
 import io.cryostat.agent.FlightRecorderHelper;
 import io.cryostat.agent.harvest.Harvester;
 import io.cryostat.agent.model.MBeanInfo;
-import io.cryostat.agent.triggers.SmartTrigger.TriggerState;
+import io.cryostat.libcryostat.triggers.SmartTrigger;
+import io.cryostat.libcryostat.triggers.SmartTrigger.TriggerState;
 
 import com.google.api.expr.v1alpha1.Decl;
 import com.google.api.expr.v1alpha1.Type;
@@ -86,6 +87,39 @@ public void start(String args) {
         this.start();
     }
 
+    // start(args) will re-parse the triggers directory, we don't need to do that
+    // for requests that come in later through the api since existing triggers
+    // are already stored.
+    public boolean append(String definitions) {
+        // Sanity check the trigger definitions before we stop/start the evaluation
+        if (!parser.isValid(definitions)) {
+            log.warn("Invalid Trigger definition {}", definitions);
+            return false;
+        }
+        this.stop();
+        parser.parse(definitions).forEach(this::registerTrigger);
+        this.start();
+        return true;
+    }
+
+    public boolean remove(String definitions) {
+        // Sanity check the trigger definitions before touching the thread
+        if (!parser.isValid(definitions)) {
+            log.warn("Invalid Trigger definition {}", definitions);
+            return false;
+        }
+        List<SmartTrigger> triggers = parser.parse(definitions);
+        // Sanity check the triggers actually exist
+        if (!this.triggers.containsAll(triggers)) {
+            return false;
+        }
+
+        this.stop();
+        this.triggers.removeAll(triggers);
+        this.start();
+        return true;
+    }
+
     public void stop() {
         if (this.task != null) {
             this.task.cancel(false);
@@ -261,4 +295,8 @@ else if (obj.getClass().equals(Long.class))
             // Default to String so we can still do some comparison
             return Decls.String;
     }
+
+    public List<String> getDefinitions() {
+        return definitions;
+    }
 }

src/main/java/io/cryostat/agent/triggers/TriggerParser.java

@@ -30,6 +30,7 @@
 
 import io.cryostat.agent.FlightRecorderHelper;
 import io.cryostat.agent.util.StringUtils;
+import io.cryostat.libcryostat.triggers.SmartTrigger;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -117,4 +118,15 @@ public List<SmartTrigger> parse(String str) {
         }
         return triggers;
     }
+
+    public boolean isValid(String definition) {
+        String[] expressions = definition.split(",");
+        for (String s : expressions) {
+            Matcher m = EXPRESSION_PATTERN.matcher(s);
+            if (!m.matches()) {
+                return false;
+            }
+        }
+        return true;
+    }
 }

src/test/java/io/cryostat/agent/triggers/TriggerParserTest.java

@@ -15,6 +15,8 @@
  */
 package io.cryostat.agent.triggers;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Duration;
@@ -24,7 +26,8 @@
 import java.util.stream.Stream;
 
 import io.cryostat.agent.FlightRecorderHelper;
-import io.cryostat.agent.triggers.SmartTrigger.TriggerState;
+import io.cryostat.libcryostat.triggers.SmartTrigger;
+import io.cryostat.libcryostat.triggers.SmartTrigger.TriggerState;
 
 import org.hamcrest.MatcherAssert;
 import org.hamcrest.Matchers;
@@ -267,6 +270,13 @@ void testMultipleComplexTriggerWithWhitespaceWhenOnlyOneTemplateValid() {
         MatcherAssert.assertThat(trigger1.getTimeConditionFirstMet(), Matchers.nullValue());
     }
 
+    @Test
+    void testTriggerValidation() {
+        assertEquals(false, parser.isValid("foo"));
+        assertEquals(false, parser.isValid("foo~bar"));
+        assertEquals(true, parser.isValid("[ProcessCpuLoad>0.2]~profile"));
+    }
+
     static List<List<String>> emptyCases() {
         List<List<String>> l = new ArrayList<>();
         l.add(List.of());